Mirror of reflector water-level gauges



March 16 1926. 1,576,897

R. BolzARD MIRROR 0F REFLECTOR WATER LEVEL GAUGES Filed June 16, 1924 lNVENTOR 2a 040] Bazlfari BY r. 756/ ATTORNEY Patented Mar. 16, 1926.

UNITED STATES BLOUL BOIZABD, OF PARIS, FRANCE;

MIRROR OI REFLECTOR WATER-LEVEL GAUGES.

Application filed June 18, 1924. Serial No. 720,404,

To all whom it may concern: I \1 Be it known that I, RAOUL BOIZARD, a citia.

zen of the Republic of France, residing at Paris, France, have invented certain new and useful Improvements to the Mirrors of Reflector Water-Level Gauges, of which the followin is a specification.

With hitherto known mirrors of reflector water-level gauges, reflection is obtained by means of a series of prismatic striae or grooves out side by side in the face of the said mirrors in contact with the liquid to be gauged.

Now, whatever the glass used, such small sized striae or grooves offer the serious drawback of becoming rapidly spoilt or easil clogged, thereby losing their reflecting qualities or powers.

.. The purpose of my invention is to provide a new reflectin mirror for boiler or other gauges that Will do away with the above stated drawbacks;

The mirror which is the object of my in vention is essentially characterized by the combination of a single prismatic ridge formed on the face in contact with the liquid to be gauged and opposite a suitably shaped convex wall formed on the outer face in such a way that the luminous rays absorbed and reflected by the ridge on the inner face will be dispersed at a wide angle by the outer convex wall, or, in other words, so that the luminous effects of the ridge will be magnified b the convex wall or lens.

In or er to make my invention more-clear- I ly understood I have illustrated, as an example, a method of makin a mirror in accordance therewith in and y drawings appended hereto, one of the figures shown thereby relating, however, to known reflector mirrors, so as more plainly to demonstrate the difference existing between the two devices.

In the said drawings:

Figure 1 is a cross section of a reflecting mirror as hitherto in use and having prismatic striae or grooves 011. its outer face;

Fi ure 2 illustrates a reflector mirror embodying all the characteristics of my invention, that is to say having a single -ridge which may be disposed'opposite a convex wall, so that the latter will magnify the luminous effects obtained by the prismatic ridge.

Fi ure 3 shows a modification of the mirror i ustrated by Figure 2.

Figure 4 indicates diagrammatically the path of the luminous rays between a single prismatic rldge and an opposite convex wall, together with the reflected and magnified lum nosity effects which are the object of my invention.

Figure 5 relates to a form of mirror which can be dressed on both its faces.

, As will be apparent from the drawings a denotes the single inner ridge and b the opposite convex wall.

The foregoing explanations will enable it to be readily understood that with the novel mirror the drawbacks offered by the reflector glass with multiple prismatic striee will be avoided since:

1. The single ridge, being larger, will wear more slowly than each of the small striae of the usual model;

2. There being but a single ridge, the danger of small grooves being clogged by the impurities contained in suspension in boiler watersis no longer to be feared.

3. Due to the magnifying of the luminous effects of the single ridge, this ridge can be so established as to leave at the edges of the mirror much more room for the joint'than is usually the case with prism-grooved mirrors.

4. The shape of themirror itself will permit it to be obtained by moulding, a method impracticable with the usual striee which must be out; whence a reduction of its cost.

As shown by Figure 5, I can, in view-of permitting both faces cd to be dressed, sink ridge a and convex wall or lens 6 in the body of the glass, so that faces c'd will protrude to a greater extent than the ridge and than the lens. -I can, then, after moulding the mirror under pressure, dress the faces cd.

I can also obtain ridge a as shown by Figure 5 and omit convex wall I), face at then being flat.

Having now particularly ascertained and described the nature of my said invention as well as the manner in which the same is to be performed, I declare that what I claim is:

1. A reflector mirror for boiler and other high pressure level gauges, comprisin an elongated glass body which is provide on 1 tial width, and said convex wall being located directly opposite the ridge so as to magnify the luminous effects produced thereby.

2. A reflector mirror, accordin' to claim 1, in which both the ridge and t e convex wall are sunk into the glass body so as to lie inwardly of the limiting planes formed by the op osite faces of said body.

3. A re ector mirror, according to claim 1, in which the ridge and the convex wall constitute companion parts, one of such parts being sunk into the glass body so as to lie inwardly of the limiting plane formed by the adjacent face of said body.

4. A reflector mirror, according to claim 1, in which the opposite faces of the glass body are dressed in order to insure tight joints; and in which the ridge and the wall have their marginal longitudinal edges spaced an appreciable distance from the longitudinal mar inal edges of said faces so as to provide re atively-wide contact surfaces for the joints.

5. A reflector mirror, accordin to claim 1,- in which the opposite faces 0 the glass body are, in the main, flat and dressed to insure tight joints; and in which the ridge and the convex wall are respectively sunk beneath said flat faces so as to lie inwardly of the limiting planes formed by said faces, said rib and wall having their marginal longitudinal edges spaced an appreciable distance from the longitudinal marginal ed es of said dressed faces so as to provide re atively wide contact surfaces for the joints.

In testimony whereof I afiix my signature.

RAOUL BOIZARD. 

